You might contact Speedway and ask them...
But, you'll probably go to Mac Van Pelt. I bought from him cause of the service factor... Was a good thing, too. I got a cluster that was poorly finished, and he was right there- no problem.
I think that the gears are expensive to tool up for and so, every supplier gets them from the same source.
That would be my opinion-
Karl
As for the 1947, depends on the engine... It's a larger heavier car. The higher gears are sure fun in a Model A-V8... Might be a bit high for starting up steep hills in the 47.